Control cable length adjuster



Jan. 9, 1951 M. FlSHBElN ET AL.

CONTROL CABLE LENGTH ADJUSTER Filed Sept. 9, 1947 .Z'A/I/E/VTOES MEYER fisflasmg M/CHAEL i/VAG-Y, 7 #2, firraewsx Patented Jan. 9, 1951 CUNTROL CABLE LENGTH ADJUSTER Meyer Fishbein, Los Angeles, and Michael J. Nagy,

Inglewood, Califl, assignors to Northrop Aircraft, llnc., Hawthorne, Calif., a corporation of California Application September 9, 1947, Serial No. 772,948

The present invention relates to control systems for actuating the prosthetic hook of an artificial arm, and the primary object of the invention is to provide a device for increasing or decreasing the length of the cable to adjust the same to the most effective length for proper functioning when the arm or hook are being used in certain positions.

The need for such a device has long been recognized, owing to the relatively short travel of the control cable obtained from the attached shoulder harness by a forward shrug of the shoulder opposite the amputated limb. This harness consists of a loop which passes under the armpit and over the shoulder, and connected to the loop is a strap which is attached at its other end to the control wire of a Bowden cable The flexible conduit or housing of the cable is anchored to the upper and lower arm components of the artificial arm, and as the harnessed shoulder is shrugged forwardly, the distance between the loop and the anchorage of the cable housing is increased, producing a pull on the control wire. The maximum available amount of shoulder movement forward I of the normal relaxed position is quite limited,

and it is the general practice, therefore, to adjust the harness so that all slack is taken out of the control wire, leaving the latter under slight tension when the shoulders are relaxed, so that the fullest use is made of the muscular movement.

amount of reduction in distance. Likewise, when.

the arm is moved to the rear of the transverse plane of the body, the distance between the upper end of the cable housin and the shoulder harness is similarly shortened, also producing slack in the control wire. This slack which is introduced into the control wire must be taken up by the initial movement of the shoulder shrug before the hook starts to open, and as a result, the amount of muscular movement available to open the hook is greatly reduced. In the extreme condition where wrist flexion is combined with a rearward position of the arm, the amount of slack produced in the control wire may be so great as to take up the entire amount of muscular movement, leaving none to open the hook. The present invention overcomes this diiiiculty by providing means whereby the amputee can adjust the length of the control wire at will to tunctionr V 3 Claims. (Cl. 287-58) vAnother object of the invention is to provide a cable length adjuster which is positive in action, and which transmits the cable pull without slipping.

A further object of the invention is to provide a cable length adjuster which is convenient and easy to operate, particularly in the case of the bi-lateral amputee having limited dexterity for manipulation of locking or adjusting devices.

Still another object of the invention is to provide a device of the class described which is compact and smooth on its external surfaces, having no sharp-edged protuberances to catch on the clothing.

The foregoing and other objects and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of the preferred embodiment thereof, reference being had to the accompanying drawings, in which:

Figure 1 is a perspective view of an artificial arm and hook, showing a control cable length adjuster embodying the principles of the invention;

Figure 2 is a similar view, showing the wrist bent in fiexio'n, and'the cable length adjuster shortened to take up the slack in the control wire;

Figure 3 is an enlarged sectional view through the cable length adjuster, taken along the line 3-3 in Figure 1; and t Figure 4 is a still further enlarged sectional view taken along the line 4-4 in Figure 3.

In the drawings, the reference numeral l0 designates the forearm shell of an artificial arm, and embedded in the outer end thereof is a wrist cap H. Mounted on the wrist cap H is a flexion unit l2 consisting of a-saddle l3 and a movable sector M. The saddle I3 is screw threaded into the wrist cap II and has a pair of spaced flanges l5 projecting therefrom. The movable sector i4 is disposed-between the flanges l5 and is connected thereto by a pivot bolt 16 for swinging movement about an axis corresponding to the wrist fiexion axis of the natural hand. The movable sector I4 is adapted to be locked with respect to the saddle l3; in a straight, extended position, or bent at an angle of either 22 ,4 or thereto, by means of a spring-pressed locking detent having an operating knob 20 projecting from the upper flange of the saddle. The detent is constructed so that the movable sector I4 is tofacilitateengaging and pressing the same with the point of another hook, as in the case of a bilateral amputee.

The utility hook is designated in its entirety by the reference numeral 2 I and includes a base 22 having a threaded stud which is screwed into a tapped socket in the outer surface of the movable sector l4. Clamped between the sector l4 and a metal washer 23, which is shouldered against the bottom end of the base 22, is a rubber washer 24, the purpose of which is to provide a yielding stop against which the base can be tightened, while at the same time permitting the hook to be turned to'any convenient position without overstressingfthe threads of the attaching stud.

Formed integrally with the base 22 and projecting forwardly therefrom is a stationary hook 25 which cooperates with a movable hook 26 in a manner well knownto those skilled in the art. The movable hook 25 is pivotally connected to the base 22 by'a pivot bolt 36, and projecting laterally from the pivoted rear end of the hook is an operating lever 3!. A rubber band 32 encircles the rear ends of the hooks 25, 26 just behind guard flanges 33, and functions to pull the hooks together so that articles may be firmly grasped between them.

The hook 2! is opened against the tension of the rubber band 32 by means of a Bowden cable control, of which only the tension transmitting wire 34 is shown in the drawing. The wire 34 passes upwardly along the arm through a spring wound conduit (not shown) and is attached at its upper end to the usual shoulder harness, worn on the opposite shoulder of the amputee. The lower end of the control wire 34 is connected to the operating lever 3| of the movable book 26 through the agency of a cable length adjuster, designated generally at 35, with which the present invention is primarily concerned.

, The cable length adjuster 35 consists of a tubular sleeve 36 which is attached to the Wire 34, a notched rod 40 slidably disposed within the tube 36 and connected atits front end to the operating lever 3i, and'a spring-pressed detent 4| which is mounted on the tube 36 and engageable with the notches in the rod 46 to lock the latter in the adjusted position. The rear end of the tubular sleeve 36 is neckeddown at 42, and the end of the wire 36 is inserted into the central hole 43 therein and soldered in place. The main portion of the sleeve 36 has a central, smooth bore 44, and the rod 46 slides within this bore.

The rod 40 has a ball 45 formed on the front end thereof, and this ball is confined within a socket 46 in an enlargedbarrelA'l forming the rear end portion of a flexible connection 48. Projecting forwardly from the barrel 41 is a slender shank 50, and on the front end of the shank is a ball which is adapted to seat in a socket 52 in the operating lever 3|. A slot 53 just wide enough to pass the shank 50, is provided in the outer end of the operating lever 3| and extends into the socket 52, so that the ball 5| can be inserted into the socket by slipping the shank 56 through the slot 53. The flexible connection 48 is merely incidental to the present invention, and forms no part thereof, being describedin more detail and claimed in the copending application of Donald M. Threewit,

Serial No. 765,750, filed August 2-, 1947 now Patent No. 2,493,841, issued January 10, 1950.

Formed in the rod 40 at equally spaced intervals along the length thereof, are, annular notches 55, each of which has a square shoulder 56 on the side toward the control wire 34, and an inclined shoulder 51 on the other side. The square shoulder 56 of each of the notches is engageable by an inwardly bent lip 60 on the spring detent 41, which projects downwardly through an opening 6! in the side wall of the tubular member 36 adjacent the outer end thereof; The lip 60 is formed on one side of a collar 62 which surrounds the outer end of the tubular member 36 and is attached on its other side to the front end of a. spring leaf 63. The collar 62 is generally elliptical in cross-section, having approximately the same inside dimension along its minor axis as the outside diameter of the tubular member 36, but being appreciably longer on its major axis, which passes through the lip 60. The collar 62 is thus loose on the tubular member 36 and is movable with respect thereto, by the amount of clearance between them, along the major axis of the collar, which is crosswise to the axis of the tubular member. In Figure 3 of the drawings, the lip 60 is located at the top of the tubular member, and the collar is urged downwardly by the spring leaf 63 so that the lip 66 seats in one of the notches 55. The bottom portion of the collar is spaced out from the sleeve, and the collar can be pressed upwardly to lift the lip 66 out of the'notch 55. The rear end of the spring leaf 63 is attached to a sleeve 64 which is slidably mounted on the outside of the tubular member 36. The sleeve 64 is held against turning on the tubular member 36 by means of an indentation 65 in one side of the sleeve which projects down into a longitudinally extending key way 66 in the tubular member. A radial flange 61 on the end of the tubular member 36 serves as a stop engageable by the collar 62 to prevent the detent unit ll from sliding endwise ofi the tubular member.

The manner of using the device is believed to be more or less self-evident from the foregoing description. When the hook is bent in flexion, as shown in Figure 2, the slack in the control cable is taken up by grasping the tubular member 36 in the other hand and pushing it forwardly so that the rod 46 is telescoped further into the tube. The lip 65 rides up on the inclined shoulder 5'! of each of the notches 55 until the lip is positioned in either the middle or front notch, as required to take up the slack. Tension applied thereafter to the control wire 34 causes the lip 66 to engage the square shoulder 56, looking the members 36, 46 together and holding them against relative movement in the direction of extension. When the hook is again swung out to the extended position, the unit 35 is restored to its original position, with the lip 60 seated in the rear notch 55, by pressing against the bottom side of the collar 62, which lifts the lip clear of Whichever shoulder it has been in engagement with and permits the tubular member and rod to slide apart.

The spring detent unit M can be removed from the tubular member 36 by pressing against the bottom of the collar 62 with sufiicient force to raise lip 66 up onto the top surface of the tubular member, whereupon the spring detent unit 4| can be pulled rearwardly off the tubular member.

While we have shown and described in considerable detail what we believe to be the preferred form of our invention, it is to be understood that such details are not restrictive, and that various changes may be made in the shape '75 and arrangement of the several parts without departing from the scope of the invention, as defined in the appended claims.

We claim:

1. A cable length adjuster comprising a tubular member having a rod member telescopically associated therewith, said rod member having a plurality of longitudinally spaced notches provided therein, a detent comprising a sleeve mounted on said tubular member, a spring leaf extending longitudinally from said sleeve, and a collar fixed to the free end of said spring leaf and loosely surrounding said tubular member, said collar being formed with an inwardly bent lip engageable with said notches to lock said members against relative movement in one direction, said lip being disengaged from said notch to release said members by pressing against the other side of said collar.

2. A cable length adjuster comprising a tubular member having a rod member telescopically associated therewith, said rod member having a plurality of longitudinally spaced notchesprovided therein, each of said notches having a square shoulder on one side and an inclined shoulder on the other, and a detent comprising a sleeve slidably and non-rotatably mounted on said tubular member, a spring leaf extending longitudinally from said sleeve, and a collar fixed to the free end of said spring leaf and loosely surrounding said tubular member, said collar being formed with an inwardly bent lip projecting through an opening in the side wall of said tubular member and engageable with the square shoulder of any one of said notches to lock said members against relative movement apart, said lip being cammed up out of said notch by the inclined shoulder thereof when said members are moved together,

and said lip being disengaged from said square shoulder to releasesaid members for extension by pressing against the other side of said collar.

3. A cable length adjuster comprising a tubular member having a rod member telescopically associated therewith, said rod member having a plurality of longitudinally spaced notches provided therein, each of said notches having a square shoulder on one side and an inclined shoulder on the other side, a spring leaf attached at one end to said tubular member and extending longitudinally thereof, and a collar fixed to the other end of said spring leaf and loosely surrounding said tubular member, said collar being formed with an inwardly bent lip engageable with said notches to lock said members against relative movement in one direction, said lip being disengaged from said notch to release said members by pressing one side of said collar against said tubular member.

MEYER. FISHBEIN. MICHAEL J. NAGY.

REFERENCES CITE-D The following references are of record in the file of this patent;

UNITED STATES PATENTS Curtis Jan. 14, 1941 

